Sewing machine



April 1, 1958 w. HEIMANN 2,828,709

- SEWING MACHINE Filed Sept. 28, 1953 r 3 Sheets-Sheet 1 Willi Heimann Aprill, 1958 w. HEIMANN 2,828,709

SEWING MACHINE Filed Sept. 28, 1953 3 Sheets-Sheet 2 In van/0r- Willi Heimann April 1, 1958 Filed Sept. 28, 1953 W. HEIMANN SEWING MACHINE 3 Sheets-Sheet 3 4 Inventor illi Hcimann United States Patent D SEWING MACHINE 5 Willi Heimann, Kaiserslautern, Germany, assignor to G. M. Pfafi A.-G., Kaiserslautern, Pfalz, Germany Application September 28, 1953, Serial No. 382,808

Claims priority, application Germany Gctober 3, 1952 3 Claims. (Cl. 112-258) The invention relates to a sewing machine.

In operating sewing machines the requirement often arises for an extension or lengthening of the machine arm to produce a socalled long arm machine. These longarm sewing machines are required when particularly broad materials are to be sewed or when the materials to be sewed are located at a large distance from the vertical machine .post and a gathering or pulling together of the materials or articles to be sewed must be avoided.

It is the foremost object of the invention to provide a sewing machine where a length variable machine arm is combined with working parts ordinarily used with normal type sewing machines.

These long-arm sewing machines require for their manufacture at the present other working devices, for instance, chip-lifting tools as the normal sewing machines.

The invention eliminates the use of these expensive manufacturing means and, therefore, denotes considerable savings and price reductions in the manufacture of long arm sewing machines; this sewing machine type, therefore, can be manufactured in conformity with the invention in practically the same manner as a normal sewing machine.

An important feature of the invention is a machine frame adapted to be used for different arm lengths in spite of the application of the same operational means which are used for the production of sewing machines having the customary arm length.

This problem is solved by the invention in the following manner.

The machine frame composed of the vertical machine post, the horizontal machine arm and the vertical machine head of a sewing machine of customary length is separated by a vertical cut applied to the arm; the machine parts thus produced are for the purpose of their conversion into a long arm machine provided with an extension member inserted into the machine arm and connected to the separated arm sections. This separation of a customary sewing machine into a long arm machine may be applied to the base plate.

The means for connecting and coupling the separated machine parts are located at the inside of the arm extension member; this has the advantage that the normal smooth outside appearance of the machine is preserved and the arm extending and lengthening member is so constructed and shaped that a smooth transition is secured of the extension member into the arm proper and that a different exterior of the arm member is avoided. In this manner the impression is maintained that the elongated machine represents a one-piece body.

A particular advantage of the long arm construction in conformity with the invention consists therein that dirt or dust cannot penetrate into the machine frame at the junction places of the arm extension with the arm proper and that the articles to be sewed will not be entangled or caught by the arm elongated extension member.

The machine shaft transiting the elongated arm is preferably constructed as one piece; however, the shaft may be divided and provided with an extension and with means to couple the separated shaft portions.

The arm dividing cut may, preferably, be in the portion of the arm located in the vicinity of the vertical machine post.

The invention will now be described more in detail and with reference to the attached drawings illustrating a preferred embodiment thereof.

In the drawings:

Fig. 1 is a side elevational view of a normal sewing machine upon its conversion into a long arm machine;

Fig. 2 is a large scale vertical sectional view of the extended portion of the machine arm;

Figs. 3 and 4 are vertical end elevational views of the machine arm as seen upon dismantling at line 3-3 and 44 of Fig. 2 respectively;

Fig. 5 is an end elevational view of the extension member, having an equal configuration at both ends;

Fig. 6 is a perspective view of the head portion of the machine adjacently located to the arm extension member;

Fig. 7 is a fragmentary vertical sectional view of the machine arm just after an application of a vertical cut to the same; and

Fig. 8 is a front elevational view of a nut.

In order to convert a normal sewing machine into a long arm machine an outer circumferential recess of the width a, see Fig. 7, is applied to the end portion of the horizontal arm, this recess being located near the machine post 1 of a customary sewing machine.- Moreover, a vertical throughgoing separating cut b is applied to the machine arm which divides the same into two outer or arm sections 2, 3, see Figs. 2 and 7.

Projections are applied to the inner face of the arm sections 2, 3, see Fig. 7; upon application of the separating out these projections are divided into sections 4, 4 and 5, 5, see Fig. 7; they are provided with bores for the reception of the anchor bolts 6, Fig. 2. Bores 7, Fig. 2, are applied to the arm section 3 and provided with screw threads for the screwing-in of the anchor bolts 6; the corresponding bores 8 in the other arm section 2 have no screw threads; they are so dimensioned that the bolts 6 may freely'pass therethrough.

The recess a is so shaped that from the arm'forming material centering flanges 9, 19 result, Fig. 7.

If the machine is to be used as a customary machine the horizontal arm remains undivided; however, the in terior portion thereof is shaped, as described; therefore the machine can be easily converted into a long arm machine by the application to the arm of said separating cut.

Upon the separation of the arm and replacement of the customary operating shaft and the needle advance shaft by longer shafts, the sections or extension member, Fig. 2, is inserted between the arm sections 2, 3 formed by the cut and the three parts, viz. the arm sections 2, 3 and the extension member 17 are connected and secured in their position by the anchor bolts 6. This connection is secured by application of the cylindrical nuts or coupling units 11, Fig. 8, which at the one end are provided with slots 12 for the application of a turning tool for the bolts 6, said bolts extending into the bores 8 and being screwed into the arm sections. The bores are enlarged at 13 for the reception of the coupling units 11. After being screwed upon the bolts 6 the coupling units 11 are supported by the shoulders 14, Fig. 2, acting as pressure faces whereby the anchor bolts 6 are subjected to tensile stresses. In Fig. 7, number 15 denotes a bore for the reception of the needle advancing shaft, not shown.

The driving shaft, also not shown, extends through the opening 16, Fig. 7.

Bores 8' and 15, Figs. 5, 2, are provided in the end portions 18 of the extension member 17 for the insertion of the anchor bolts 6 and the passage of the needle advancing shaft, not shown. Bore 15 corresponds with bore 15in the arm section 2, Fig. 2, and with bore 15", Fig. 3, in the arm portion 3 for the passage of the needle advancing shaft, not shown.

In order to properly center member 17 on flanges '9, 10 of the sections 2, 3 a bore 19, Fig. 5, is provided in the end faces thereof; through the upper portion of this bore also pass some of the anchor bolts and the driving shaft, not shown.

The extension member 17 (Figs. 1, 5) has the function of a distance securing member between the arm sections 2 and 3, the outer faces thereof contacting the recess-es provided in said sections, Fig. 1; the extension member is so shaped and fitted into the horizontal machine arm that a smooth surface is created at the outside thereof (Figs. 1 and 2).

If the machine is sold as a normal machine, the horizontal arm is left as a single undivided member; the arm will only be divided if the machine is to be used as a long arm machine.

It is obvious that the shown coupling means of the extension member 17 with the arm sections 2, 3 may be replaced by other suitable connecting members.

The machine shown in Fig. l is a long arm two-needle machine, provided with needles 21, Fig. 1. The needles cooperate with stitch forming tools (not shown) located in the upper portion of a column 22 located upon the base plate 20.

Since certain changes may be made in the above described arrangement and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all'matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What I claim is:

1. In a sewing machine having a post, the combination comprising a tubular arm connected to said post and formed of a series of three aligned abutting sections including two outer sections spaced apart from each other and one being connected to said post, and an inner section removably positioned between and mounted on said outer sections, each outer section including at its end portion an apertured transverse end wall, said inner section including at each opposite end portion an apertured transverse end wall, interengaging means between each end portion of said inner section and the end portion of each outer section comprising an arcuate projection on some of said end walls recessed from the outer contour of the wall face forming a shoulder thereon, and an arcuate flange on the other end portions each operable to engage a projection, the external contour of said innersection matching that of said outer sections near the end walls thereof, whereby said sections form on said arm for a longitudinal portion extending throughout and beyond the length of said inner section a continuous uniform external surface, and securing means operable for releasably mounting said inner section in position on said outer sections, said securing means being disposed entirely within the interior of said aligned sections for concealment.

2. In a sewing machine, as claimed in claim 1, the end walls of each outer section having apertures aligned with those of the other outer section, the end walls of said inner section having aligned openings, said apertures being aligned with said openings, said securing means including bolts extending through said apertures and openings and tightening means engaging said bolts to said outer sections and operable to tension said bolts to tighten the abutment between the respective sections.

3. In a sewing machine as claimed in claim 2, said tightening means including threads on the opposite ends of each bolt, the apertures of one of said outer sections including a thread, each bolt being at one end in threaded engagement with a threaded aperture, a nut in threaded engagement with the opposite end of each bolt hearing from the interior against the end wall of the other outer section.

References Cited in the file of this patent UNITED STATES PATENTS 62,746 Hayes Mar. 12, 1867 247,303 Case Sept. 20, 1881 380,486 Honinger Apr. 3, 1888 418,890 Diamond et a1 Jan. 7, 1890 1,151,763 Dieter Aug. 31, 1915 1,307,520 Schurger June 24, 1919 1,928,486 Gruman Sept. 26, 1933 2,144,706 Pescara Jan. 24, 1939 2,561,643 Adler July 24, 1951 2,645,509 Valenta July 14, 1953 2,709,978 Adler June 7, 1955 FOREIGN PATENTS 469,477 Italy Mar. 2, 1952 

